Removable media storage libraries, e.g., automated tape libraries, often support partitioning the physical library into two or more logical libraries for presentation to the host application. Each host application then believes it has a dedicated library for use thereby providing a level of transparency to the host application. Each partition typically consists of a set of dedicated resources assigned to the partition, comprising data transfer devices, such as tape drives, storage slots, import/export slots, and removable media. The removable media can include data tape, which is tape that includes data that has been inputted via the particular host application, and scratch tape, which is tape that does not include any data that has been inputted via the particular host application. A robotics subsystem for moving resources between and/or among the partitions is then typically shared among the partitions. In some instances, the import/export slots may also be shared among the partitions.
One of the challenges with the use of partitions in a removable media storage library is in resource planning. The quantity of each resource, including drives, slots and media, needs to be identified in advance of defining and configuring a partition. Unfortunately, the need to identify specific quantities of resources in advance can be difficult and can lead to potential problems within individual partitions and within the storage library as a whole. For example, allocating too many slots to any one partition that remain unoccupied may create a shortage for another partition that needs them. Additionally, allocating too few slots to any one partition may not provide sufficient storage for removable media for that partition.
Further, current logical library partitions are separate entities that do not allow quick and efficient movement of resources from one logical library partition to another logical library partition. For example, the current system does not allow an application or user to move a tape cartridge from one logical library partition to another without first exporting the tape cartridge out of the library and then importing the tape cartridge back into the library. Accordingly, when resource allocation issues are encountered, a system administrator might be required to manually reconfigure several partitions in order to effectively re-allocate the existing resources. For instance, if one partition requires more media, and the partition has no more available storage slots, an administrator may reduce the number of slots assigned to one or more other partitions and then assign the slots to the partition needing them. This process ends up being cumbersome, and can affect several partitions. Further, in this instance, the configuration process is not done in direct terms of the resource needed, i.e. media. This is especially true of open systems-based storage libraries, such as those that support the SCSI Media Changer command set. Instead, the reconfiguration is done indirectly, in terms of the slots for the media, rather than the media itself.
Additionally, host accessible movement of resources from one partition to another could lead to the unintentional compromising of one partition's data tape into another partition's scratch tape.